Fixes heater/freezer icon updating if power cut
Readds powered pump to air injector
Fixes APC load totals periodically doubling

Also fixes areas updating excessively when update_use_power() was
called.
Fixes pressure regulator mode
Fixes critical gas freezer bug
Adds atmos/supermatter debug messages
Powernets

Moved powernet datum definition to powernet.dm
Improved APC load balancing.
Updated SMES charging to work better with new APC/powernet code.
Supermatter balance

Attempts to rebalance SM to work with new atmos machinery. Testing with
a 2-freezer 2-canister default setup, the engine can run to 500 kW at
700 K.
Engine piping update
Adds engine waste intercooler

Also fixes pipes in space having the wrong layer set.
Allows heater/freezer construction dir to be set
Adds heater/freezer boards to tech storage
Fixes #6269
Map ocd

Rearranged tech storage a little.
Adjusts airlock reserve air pressures

Adjusts airlock reserve air pressures for faster cycling.
Renames syndicate mothership area, fixes temp_factor calc
Fixes atmos control computers not being able to turn their devices on or off
Adds atmos SMES
Emergency shutters down have pressure/temperature difference overlays.

Based on the emergency shutter from Paradise.
Merge pull request #6291 from mwerezak/engine

Dev-Freeze Engine Tweaks + Powernet Fixes